The WMUR Granite State Poll shows that Hillary Clinton is still the top pick for Democrats in 2016. If the primary were held today, 59 percent of likely Democratic voters said they would pick Clinton, with 14 percent saying they would choose Vice President Joe Biden.

U.S. Sen. Elizabeth Warren, D-Mass., was the pick of 8 percent, and 5 percent said they would voter for U.S. Sen. Bernie Sanders, I-Vt.

While Clinton still holds a sizable lead, her numbers have slipped somewhat in recent months.

"I think what happens in any race like this if there is anyone who is that much of a frontrunner, it becomes boring," said Andy Smith of the University of New Hampshire Survey Center. "There's nothing to talk about. There's nothing to look at. If you are a political activist, you start to look at some of the other candidates just for something to do."

On the Republican side, there is no clear frontrunner. New Jersey Gov. Chris Christie is the most popular choice, with 19 percent of likely Republican voters saying they would vote for him, followed by 14 percent supporting U.S. Sen. Rand Paul, R-Ky.

"Let's be clear," said GOP strategist Jim Merrill. "This is the most wide-open field we have in memory here in New Hampshire. There's no heir apparent. There's no frontrunner."

But that all changes if former Republican presidential candidate Mitt Romney were to enter the fray.

"What's fascinating is that Republicans really don't have a lot of enthusiasm for any one of these candidates," Smith said. "So if you throw somebody else's name in the mix, you can see some things changing."

The poll shows that if Romney ran, he would get 39 percent of the vote if the primary were held today. None of the other candidates crack single digits.

There is no indication Romney is planning to run again.

The poll of 889 randomly selected New Hampshire adults was conducted for WMUR by the UNH Survey Center by landline and cellphone from June 19 through July 1 and has a margin of sampling error of plus or minus 3.8 percentage points.

A subset of 257 likely Democratic primary voters has a margin of sampling error of plus or minus 6.1 percentage points, and a subset of 251 likely Republican primary voters has a margin of sampling error of plus or minus 6.2 percentage points